Comparing Forces in Car Collisions

[JL-Wsixx]

Homework Statement

1. A red car with a velocity of 20mph north collides with a blue car that is stopped at a stoplight. On which car is the force greater?

2. A red car with a velocity of 25mph north collides with a blue car with a velocity of 15 mph north. Which one feels a greater force?

3. A red car traveling at 25 mph north collides with a blue car traveling at 15mph south. Which car experiences the greater force?

Homework Equations

The Attempt at a Solution

 

[tiny-tim]

Welcome to PF!

Hi JL-Wsixx! Welcome to PF!

Tell us what you think, and then we'll comment

 

[SammyS]

What does Newton's 3rd Law say?

 

[JL-Wsixx]

Well, for #1 I think that the red car would have a greater force being that it's in motion with a v=20 mph and not a standstill like the blue car which has a net force=0.

For #2, again I think that the red car has a greater force because its velocity is greater than the blue car same as with problem 3.

Newton's 3rd law says that when one object exerts a force on a second object, the second exerts an equal and oppositely directed force on the first.

So does this mean that there force are the same?

 

[tiny-tim]

Newton's 3rd law says that when one object exerts a force on a second object, the second exerts an equal and oppositely directed force on the first.

So does this mean that there force are the same?

erm … yes!

 

[JL-Wsixx]

So, the red cars greater velocity or the directions of the cars doesn't come into affect?

 

[tiny-tim]

Correct.

 

[JL-Wsixx]

Cool, thanks :)